[Bug libstdc++/79820] std::ifstream sets errno to zero

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79820

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Author: redi
Date: Wed Aug  9 17:52:10 2017
New Revision: 250993

URL: https://gcc.gnu.org/viewcvs?rev=250993&root=gcc&view=rev
Log:
PR libstdc++/81751 don't call fflush(NULL)

        PR libstdc++/79820
        PR libstdc++/81751
        * config/io/basic_file_stdio.cc (sys_open(FILE*, ios_base::openmode)):
        Call fflush on the stream instead of calling sync() while _M_cfile is
        null. Restore original value of errno.
        * testsuite/ext/stdio_filebuf/char/79820.cc: New.
        * testsuite/ext/stdio_filebuf/char/81751.cc: New.

Added:
    trunk/libstdc++-v3/testsuite/ext/stdio_filebuf/char/79820.cc
    trunk/libstdc++-v3/testsuite/ext/stdio_filebuf/char/81751.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/config/io/basic_file_stdio.cc